I don't think my car would have been this stiff without the strut bar. Floor jack placed under rear lift point only.

I mean, I know the purpose of a strut bar, but, for these no brand no name strut bar, how can I tell it work as some as OEM or ACS, which I trust their products. Some people might say its just a bar that hold the car together better, but, how do i know if these no brand aftermarket ones works well?? so it leads to my previous question that, how can I tell its not just a random bar, but its a carefully engineered struct bar??

I mean, I know the purpose of a strut bar, but, for these no brand no name strut bar, how can I tell it work as some as OEM or ACS, which I trust their products. Some people might say its just a bar that hold the car together better, but, how do i know if these no brand aftermarket ones works well?? so it leads to my previous question that, how can I tell its not just a random bar, but its a carefully engineered struct bar??

I think some important things to consider are:
*The rigidity of the material used and the design of the bar.
*Strength of the pivot points

Now imagine that you are looking at your engine bay from the top without the hood. The strut bar towers can be seen from above. Pretend that the O's are the front strut towers.

O......O

and by bracing those towers together, we are minimizing body flex by preventing inward displacement:

-->O....O<--

and outward displacement:

<--O.........O-->

Now I know I haven't answered your question yet, Elaine, because I know you know all of this already.

Now if you were to weld and attach both strut towers together with straight 4130 chrome moly tubing, you would effectively prevent the body from flexing inwardly and outwardly, right?

The problem is that the engine is in the way, so you must put a bend in the tube. So the next questions you may ask yourself are "how rigid is the strut brace?" and "how would bending the bar affect rigidity?"

More importantly, it is not practical to weld a solid piece to the strut towers, so we must be able to attach and detach the strut bar. So now look at the attachment points. You'll have to agree that these are the potentially weak points of the design. The OEM strut bar that Long and I have utilize fairly thick (I believe they are 8mm) bolts with hexagonal heads and/or torx. However, the bar is hollow (good for being light). The design seen in this thread seems to use solid aluminum, but it's in three pieces. I would be most concerned about the bolts that are used to attach them. Will they loosen in time with body flex?

Now imagine that you are looking at your engine bay from the top without the hood. The strut bar towers can be seen from above. Pretend that the O's are the front strut towers.

O......O

and by bracing those towers together, we are minimizing body flex by preventing inward displacement:

-->O....O<--

and outward displacement:

<--O.........O-->

Now I know I haven't answered your question yet, Elaine, because I know you know all of this already.

Now if you were to weld and attach both strut towers together with straight 4130 chrome moly tubing, you would effectively prevent the body from flexing inwardly and outwardly, right?

The problem is that the engine is in the way, so you must put a bend in the tube. So the next questions you may ask yourself are "how rigid is the strut brace?" and "how would bending the bar affect rigidity?"

More importantly, it is not practical to weld a solid piece to the strut towers, so we must be able to attach and detach the strut bar. So now look at the attachment points. You'll have to agree that these are the potentially weak points of the design. The OEM strut bar that Long and I have utilize fairly thick (I believe they are 8mm) bolts with hexagonal heads and/or torx. However, the bar is hollow (good for being light). The design seen in this thread seems to use solid aluminum, but it's in three pieces. I would be most concerned about the bolts that are used to attach them. Will they loosen in time with body flex?

hahaha........ you really explain the question in detail. Thanks.
Anyone wants to try it and let us know??

I haven't, but on my Z4 I get the same effect with no mods (I know it's smaller..... ) but just curious??

I bet you'd be able to get the same effect (front wheel lifting) without the bar

This would be a good question for Long to answer. He's jacked up his car and changed the wheels more times than I have washed my car. I have never seen the front wheel come off the ground almost exactly the same distance as the rear wheel. The stiffness of the car is like night and day post-sway bar and strut bar when going up a steep driveway or across a speed bump diagonally.

Went to my dealership today for an oil filter which they did not have but noticed the Strut bar from Dinan on the wall. I think the car is stiff enough and doesn't need it but I guess we have some people that likes more stiffness.